Grinding machine



w. 4, 1932. 0 Boom ET AL 11,880,736

GRINDING MACHINE Filed May 27, 1930 4 Sheets-Sheet l gmwnl ow WZQWM C. BOOTH ET AL GRINDING MACHINE 4 Sheets-Shet Filed May 27, 1930 Oct. 4, Q BOOTH ET AL GRINDING MACHINE Filed May 27, 1930 4 Sheets-Sheet 3 swuentot @Ct. 41-, 1932. C BQQTH ET AL I 1,83Qfi3fi GRINDING MACHINE Filed May 27, 1950 4 Sheets-Shet 4 Patented I Get. I932 UNITED STATES I PATENT OFFICE GLEHENT BOOTH AND FREDERICK S. HAAS, OF CINCINNATI, OHIO, ASSIGNORS, BY MESNE ASSIq-NMEN'IS, TO THE HEALD MACHINE COMPANY, OF WORCESTER, MASSACHU- SETTS, A CORPORATION .OF MASSACHUSETTS GRINDING MACHINE Application w m '27, mo. serial No. 456,212.

interfering with the production of the machine. .These requirements are especlally pertinent in regard to the use of continuous high production, precision grinding machines.

It is, therefore, one of the principal objects of the present invention to provide an improved retrueingmechanism for use with a high production automatic grinding machine.-

Another object of the present invention is the provision of a grindlng wheel retrueing .or redressing mechanism operable in cyclic sequence with the normal cycle of operation of the machine.

Another object of the present invention is the provision of improved means, automatically operated for periodicallv redressing or retrueing the active face of the grinding wheel without materially interfering with the constant production of the grinding machine.

Other objects and advantages of the present invention should be readily apparent. by reference tothe following specification considered in conjunction with'the accompanying drawings forming a part thereof and it is to be understood that anyv modifications may be made in the exact structural details there shown and described within the scope of the appended claims without departing from or exceeding the spirit of the invention.

In the drawings:

Figure 1 is a front elevational view of a grinding machine embodying the improvements of this invention.

Figure 2 is-a rear elevational view of the device shown in Figure 1.

Figure 3 is a sectional view of one of the switches shown in Figure 2.

Figure 4 is a sectional view taken on line 4-4 of Figure 2.

Figure 5 is a sectional view on line 5-5 of Figure 4.

Figure 6 is a sectional view on line 6-6 of Figure 2.

Figure 7 is a sectional view taken on line 77 of Figure 6.'

Figure 8 is a sectional view taken on line 88 of Figure 6.

Figure 9 is a sectional view taken on line 9-9 of Figure 2, and

Figure 10 is a diagrammatic view illustrating the hydraulic and electrical circuits involved in this invention.

Throughout the several views of the drawings similar reference characters are employed to denote the same or similar parts.

For the purpose of illustration and description the invention .has been shown in the drawings asapplied to an internal grinding machine or hole generator. The device may comprise a bed 10 having formed at the upper end thereofin spaced parallel planes ways 11 and 12. Su ported on the ways 11 for guidance there y is a wheelhead 13 having a prime mover or motor 14 coupled for rotationwith a spindle 15 carry.- ing a small diameter or internal grindin wheel 16. The said wheel-head 13 is adapte to be reciprocated byan hydraulic medium 'in Figure 10, the medium passes from the casing 21 through the conduit 23'to the right hand side of cylinder 25 for actuating a piston 26 contained therein. The medium is discharged from-the cylinder aheadof the piston throu h the conduit 24 to be directed through con uit 27 to' a casing 28 containing a start and stop valve 29 which directs the medium through a conduit 30'to. the sump or tank 17. The reversing valve 22 has extending therefrom a valve stem 31- coupled *for shifting movement with a rock shaft 32a on which is mounted an actuating lever 33. The lever 33 is positioned between and oscillated by the opposed abutting faces of shifter dogs 34 and 35 adjustably mounted in a T-slot 36 formed in the forward face of base plate 37 of wheel-head 13. The shifting movement of the piston 26 is transmitted through a piston rod 38 connected with the said base plate 37.

The wheel-head is reciprocated lon 'tudinally of the ways, as noted above, y the hydraulic medium which. enters either one side or the other of the cylinder 25. This medium is automatically directed throu h the valve 22 being controlled by .the shifting of said valve upon engagement of the shifter arm 33 with the trip dogs 34 and 35.

- Supported and guided by the ways 12 is I a slide 39 having a dove-tailed uide 40 exother.

along the ways 12 to position the work piece larly shaped tending therefrom and receive in a simi 1guide way 41 formed in the base of work ead 42. The work-head 42 comprises a work supporting blade 43 hav-. ing an angularly inclined top 44 peripherally to frictionally control and rotate same. A

second rotatable member 47 is mounted on theother side of thework support 43 for holding the work 45 and surface of the control member 46 in engagement with one an- The work-head is reciprocated adjacent the ipding wheel 16 for operation thereon to e ecta stock removal therefrom and to a position'remote from the said grind ing wheel whereby to replace the finished work piece with an unfinished one. The reciprocation of the work-head 42 away from the grinding .wheel 16 is automatically controlled by a size control device mounted adjacent the work .piece, not shown in the present drawings. Upon reaching the end of its stroke remote from'the grinding wheel 16, an automatic ejector mechanism f indicated by the numeral 48 is brought into play for replacing'the finished work piece. This automatic ejecting mechanism automatically initiates a return movement of the work-head 42 toward the grinding wheel 16. The workhead 42 is adapted to be actuated longitudinally of the guide ways 12 by. the hydraulic medium.

As shown in Figure 10, the medium passes from the pressure line 20 through a conduit 49 to a valve casing 50 enclosing a slide valve 51 for directing the medium into either conduit 52 or 53. As shown, the medium passes through conduit 52 to the right hand end of cylinder 53a for actuating tion on the work piece carried thereby and automatically held in this position during the operation on the work piece. The means for stopping the work-head in this position comprise a trip dog 61 adjustably secured in aI-shaped slot 62 formed in the forward face of the slide 39. This dog 61 engages and oscillates a lever 63 pivotally mounted at one end to the bed 10 and having its upper end pivotally connected to a link 64. The link 64 is operatively coupled with a rock shaft 65 connected with the valve stem extending from the valve 51 whereby the said valve may be shifted to a neutral position. The valve 51 may also be manually operated through a lever 66 which is keyed or otherwise secured on the end of the said rock shaft 65. After the work-head 42 has been stopped adjacent the grinding Wheel 16 the stock is removed from the work-piece by feeding the work-head proper transversely of the slide 39 along the interengaged guideways 40 and 41. This transverse feeding of the cross head 42 is effected through a cross feed mechanism indicated in general by the numeral 60.

From the foregoing description it will,be noted that the operation of the machine is purely automatic commencing with the introduction of the work piece by automatic loading means, automatically bringing'the work piece into proximity with the grinding wheel to effect a stock removal therefrom, automatically controlling the size of the work piece, automatically retracting the work piece and its supporting and rotation controlling head from the grinding wheel after the work piece has been reduced to the desiredproper size and then automatically ejecting the work piece from the machine.

To maintain the active surface of the grinding wheel 16 and not materially interfere with the cyclic operation of the machine there has been provided an improved retrueing mechanism so coupled into the machine as to function at a predetermined time in cycliczsequence. To this end the work-head 42 has formed in the rear of its slide 39 a T-shaped slot 67 adjustably carrying dogs 68 and 69. I The dog 69 has an inclined face 70 for engagement with a-roller 71 on the end of a plunger 7 2 to depress same thereby. The plunger 72 is vertically shiftable through a through its cylinder 102 housing 7 3 mounted onthe rear wall of bed 10. J ournaled in the walls of the housing 73 is a shaft 74 having pinned or otherwise secured thereto the lever 75 from which a tongue 76 extends. The tongue 7 6 passes through a slot 77 formed "intermediate the ends of the plunger 72 whereby depression of the plunger 72 rocks or oscillates the lever 75 and shaft 74. The oscillation of the lever 75 is limited by an adjustable abutment screw 78 carried by the housing 73 and abutting the end of the tongue 76. A spring pressed plunger 79 engages the other end of the lever 75 for holding the plunger 72 in an upward normal position in the path'of movement of the dog 69. Keyed or otherwise secured on the shaft 74 for oscillating movement therewith is a crank arm 80 having pivoted to its upper end a pawl 81' cooperating with the teeth on ratchet plate 82. The ratchet plate 82 has a sleeve 83 extending therefrom and is loosely journaled on the shaft 74 and extends through a bearing lug 84 formed integral with cover plate 85 secured to the outer end of the housing 73. A yielding friction shoe a 86 is mounted within a suitable bore formed in the plate 85 and engages the sleeve 83 to prevent inadvertent or promiscuous rotation of the said sleeve 83. Loosely journaled on,

the sleeve 83 but coupled for movement with the ratchet plate 82 is a cam plate 87 having one or more projecting cam points 88. A spring 89 having one end secured to the pawl 81 and the other end fixed to the housing or other fixed member is provided for holding 88 may be provided around the periphery of cam plate-87.

The cam lug 88 is adapted to depress spring pressed plunger 90 to close switch91 electrically connected through leads 92 and 93 with the main electric lines 94 and 95 controlling and energizing the solenoid 96 for shifting valve lever 97. At the time the switch 91 is closed the work-head 42 is returning from its position adjacent the grinding wheel 16 and the diamond or cutting tool, as shown in Figure 2, is positioned intermediate the edge of the wheel 16 and the adjacent end of the spindle mounting of the wheelhead 13. Simultaneously with the shifting of the valve 57 the hydraulic medium under pressure passing through conduit 98 is connected through cannelure 99 of the valve 57 with the conduit 100 for actuating piston 101 The piston 101 is ure 9 and has extending therefrom rod 103 carrying post 104 in which is secured the diamond point or dressing tool. 105. The medium within the cylinder 102 ahead of the piston 101 was discharged through conduit 106 to the main discharge line 30 for return to the tank or sump 17.

'The wheel-head13 has been constantly reciprocating back and forth and has adjustably mounted in a T-slot 107 formed in the rear face of wheel-headbase plate 37atrip dog 108 provided with an inclined face 109. This face 109 engages a depressible plunger-110 for closing a switch 111. As shown dia grammatically in Figure 10, the switch 111 is wired in series with switch 112 of the double make and break switch 113 as well as in series with a third switch 114. The said switches are in series with a solenoid for operating the starting and stopping valve 29 through a pivotally mounted valve shifter lever 116. The electrical circuit including the switches 111, 112 and 114 and the solenoid 115 comprises a wire 117 extending from the positive main 94 to oue'terminal of the switch 114extending from the other terminal of the said switch 114 to one terminal of switch 112. The wire then extends from the second terminal of switch 112 to one terminal of the switch 111 continuing from the second terminal thereof throughthe solenoid 115 back to the negative main 95. The switch 113, in practice, comprises a pair of switches, the above mentioned switch 112 and a switch mounted side by side, as seen in Figure 4, each comprising a yieldable de ressible plunger 118 adapted to be engage depressed by. the valve shifter lever 116 which has formed at its upper end beveled cam faces 8 119 and 119a. The switch 114 likewise comprises a depressible plunger-114a adapted to be depressed by the valve shifter lever 97 to close the switch at the time the said lever is actuated to shift the main valve 57. From this it will be seen that upon the completion of the stroke of the wheel-head 13 away from the work-head 42 after the closing of switch 91, the switch 111 will'be closed to-complete an electrical circuit through the solenoid 115 to actuate the stop valve shifter lever 116 to shift the said stop valve to the right, as seen in Figure 10, and prevent further discharge of the medium through conduit 27 and consequently stop the reciprocation of wheel-head 13. At thetime'of the shifting of the start and stop valve 29 the valve shifter lever 116 actuates the make and break switch 113 breaking the circuit through the switch 112 thereof and closing the other switch 120.

The switch 120 is wired in series with a second switch 121 at this time open to break the circuit. The switch 120 is also wired in series with a solenoid 122 coupled with the start then advanced to the position shown in Fig-- and stop valve shifter lever 116 while the and simultaneously switch 121 is wired in series with a solenoid 123 for actuating the main valve shifter lever 97. The circuit including switches 120 and 121 and solenoids 122 and 123 comprises a wire,124 extending, as seen in Figure 10, from the positive main 94 to and through the solenoid 123 to one terminal of the switch 121. This wire then extends from the other terminal of the switch 121 to one terminal of the switch 120 and continues from the other terminal thereof through the solenoid 122 back to the negative main electrical line 95.

At the time of the shifting of the main valve 57 the flow of the discharged medium through the conduit 56 from the cylinder 53.

was shifted on passing from the casing of the main valve 57 from the normally open conduit 58 to the conduit 125 controlled by a choke valve 126 to slow down the movement taneously energize the said solenoids 122 and 123. This restores the stop and start valve 29 and main valve 57'to their normal positions and permits the operation of the mechanism in its normal manner. At the same time the shifting of the main valve 57 connects the conduits 106 and 100 of the diamond controlling cylinder 102, as shown in Figure 10, permitting the flow of the medium under pressure through the conduit 106 to retract the diamond and discharging the medium back of piston 101 through the conduit 100.

As was suggested above the cam plate'87 may have any desired number of projecting cam points 88 therearound and is so coupled through the adjustment of stop 78 to actuate. the switch 91 after the completion of each work piece or at the completion of any desired number of such pieces. lach reciproeating movement of the work-head 42 depresses the plunger 7 2 a given amount gradually advancing the cam lug or lugs SS-to.

close the switch 91 at the desired point and efl'cct a shifting of the main valve 57 The operation of the device is as follows:

Assuming a work piece has just been completed and the size control device has effected a shifting of the valve 51 to retract the work-head 42 from the grinding wheel 16. Assuming further the parts within the easing 73 arein the position shown in Figure 7. Retraction of the work-head 42 will cause the dog 69 to depress plunger 72 and throw the cam 88 through cam plate 87 to depress plunger 90 of the switch 91 thereby completing the electrical circuit which includes. the

solenoid 96 and oscillate the valve shifter lever 97. At this time. the work-head 42 will be in the position shown in Figure 2 and the shifting of the valve 57 will reduce the speed of the said work-head to the accepted trueing speed. At the'same time the wheel-head 13 upon its retracting stroke will through the dog 108 close the switch 111 and complete an electrical circuit through the switch 114 )which was previously closed upon the throwing of the valve shifting lever 97. This electrical circuit energizes .the solenoid 115 and through the valve shifter lever 116 throws the starting and stopping valve 29 to check or stop the movement of wheel-head 13 and hold same in a stationary fixed position. The work-head 42 travels rearwardly at the slow trueing speed until the engagement of dog 68 with plunger 127 to close the switch 121. This switch 121 is not closed until the entire surface of the grinding wheel 16 has been traversed by the diamond or trueing-tool 105.

Upon the closing of switch 121 an electrical circuit is completed through the switch 120, which was previously closed through the actuation of valve shifter lever 116 for energizing the solenoids 122 and 123. These solenoids 122 and 123 return the starting and stopping valve 29 and main valve 57 to their normal operating positions at which time the cycle of the machineis re-established for normally producing finished work pieces.

From the foregoing it will be noted that an improved grinding wheel, trueing or diamonding mechanism has been provided for use with a high production automatic grinding machine. It is believed that the operation thereof will be thoroughly understood and the advantages appreciated.

lVhat is claimed is:. a

1. In a grinding machine the combination of a bed or support, a grinding wheel earriage carried thereby and reciprocable longitudinally thereof, a grinding wheel rotatably carried by the carriage, means supporting a work piece and reciprocable longitudinally of the bed toward and from the grinding wheel to present a work piece carried thereby in operative position relative to the grinding wheel, means for reciprocating the toward and from the grinding wheel, a dressing tool carried'by the work-head for resurfacin the active face of the grinding wheel, hy raulic means for effecting reciprocation of the wheel-head and work-head, means operable by the said heads for stopping movement of the wheel-head and reducing the rate of movement of the workhead, and means simultaneously operable with change of movement of the heads for actuating the redressing tool toward the grinding wheel to effect the said redressing of the grinding wheel when the wheel-head is stopped.

3. In a device of the class described the combination of a bed, a grinding wheel carriage carried thereby and reciprocable longitudinally thereof, a grinding wheel rotatably supported by the carriage, a trueing tool carried by the bed reciprocable longitudinally thereof in a plane parallel with the plane of movement of the carriage, an hydraulic circuit including an hydraulic medium for actuating the carriage and trueing tool, a

. valve controlling the flow of the medium for starting and stopping the movement of the carriage, a valve for changing the rate of flow of the medium to change the rate of movement of the trueing tool, and means operabl'eby the said wheel-head and trueing tool for actuating the valves.

4. In an automatic trueing device for use with high production grinding machines the combination of a bed, a grinding wheel carried thereby and reciprocable longitudinally thereof, a piston operatively connected with the wheel-head, an hydraulic medium for actuating the piston and wheel-head, a valve for stopping the flow of the medium for stopping the movement of the wheel-head, a trueing tool carriage carried by the bed and reciprocable longitudinally thereof, a retractable trueing tool on the carriage, a piston connected with the trueing tool carriage, a piston supporting the trueing tool, an hydraulic medium for actuating the carriage piston and trueing tool piston, a valve controlling the flow of the medium to the said pistons, and means operable by the movement of the grinding wheel and by the movement of the trueing tool carriage for actuating the valves to stop the said movement of the grinding wheel, change the rate of movement of the trueing tool carriage and position the trueing tool in the path of movement of the grinding wheel.

5. In a grinding machine the combination of a bed, a pair of slides carried thereby and actuable longitudinally thereof, a rotatable grinding wheel carried by one of the slides, a redressing tool carried by the other slide, hydraulic means for actuating the slides including a piston for each slide, an hydraulic medium for actuating the pistons, a conduit extending from each piston for the medium, a valve in each conduit, and means operable by the slides for actuating the valves to control the flow of the medium and stop the movement of the slides supporting the grinding wheel and change the rate 0 movement of the trueing tool slide.

6. In a grinding machine the combination of a bed, a pair of slides carried thereby and actuable longitudinally thereof, a rotatable grinding wheel carried by one of the slides, a redressing tool carried by the other slide, hydraulic means for actuating the slides including a piston for each slide, an hydraulic medium for actuating the pistons, a conduit extending from each piston for the medium, a valve in each conduit, means operable by the slides for actuating the valves to control the flow of the medium and stop the movement of the slide supporting the grinding wheel and change the rate of movement of the trueing tool slide, and means operable by one of the valves to position the trueing tool in the path of movement of the grinding wheel to redress the active surface thereof.

7. In a grinding machine the combination of a bed, a pair of slides carried thereby and actuable longitudinally thereof, a rotatable grinding wheel carried by one of the slides, a redressing tool carried by the other slide, hydraulic means for actuating the slides including a piston for each slide, an hydraulic medium for actuating the pistons, a conduit extending from each piston for the medium,

a valve in each conduit, means operable by the slides for actuating the valves to control the flow of the medium and stop the movement of the slide supporting the grinding wheel and change the rate of movement of the trueing tool slide, means operable by one of the valves to position the trueing tool in the path of movement of the grinding wheel to redress the active surface thereof, and means operable by the trueing tool slide for simultaneously actuating the valves to restore them to their normal positions for effecting a movement of the grinding wheel slide and reciprocating the trueing tool slide at its normal speed.

8. In a grinding machine the combination of a bed, a pair of slides carried thereby, and translatable longitudinally thereof toward and from one another, a grinding wheel rotatably carried by one of the slides, means rotatably supporting a work piece carried-by the other slide, a trueing tool carried by the work supporting slide having a position adj acent the active face of the grinding wheel and a position remote therefrom, hydraulic means for effecting the translation of the grinding wheel slide and work supporting slide and for positioning the trueing tool, a"

' of the trueing tool, means for shifting sition of the trueing tool, and means carried by the slides for effecting the actuation of the valves.

9. In a grinding machine the combination of a bed, a pair of slides carried thereby and translatable longitudinally thereof toward and from one another, a grinding wheel r01- tatably carried by one of the slides, means rotatably supporting a work piece'carried by the other slide, a trueing tool carried by the work supporting slide having a position adjacent the active face of the grinding wheel and a position remote therefrom, hydraulic means for effecting the translation of the grinding wheel slide and work support1ng slide, a piston operatively connected with each slide and operated by the hydraulic means, a conduit for each piston, a valve in each conduit for controlling the flo w of the hydraulic medium therethrough to control the movement of the slides and the 'positipln t e valves for stopping the movement 0 the grinding wheel slide, changing the rate of movement of the work supporting slide and for positioning the trueing tool adjacent the active face of the grinding wheel and retracting same therefrom, and a depressible plunger carried by the bed operable by the work supporting slide for setting in motion the last mentioned means.

10. In a grinding machine the combination of a bed, a pair of slides carried thereby and translatable longitudinally thereof toward and from one another, a grinding wheel rotatably carried by one of the slides, means rotatably supporting a work piece carried by the other slide, a trueing tool carried by the work supporting slide having a position adjacent the active face of the grinding wheel and a position remote therefrom, hydraulic means for effecting the translation of the grinding wheel slide and work supporting slide, a piston operatively connected with each slide and operated bythe hydraulic means, a conduit for each piston, a valve in I each conduit for controlling the flow of the hydraulic medium therethrough to control the movement of the slides and the position of the trueing tool, one of said valves effecting the starting and stopping of the grinding 11. In a grinding machine thecombina tion of a bed, a pair of slides carried thereby and. translatable longitudinally thereof toward and from one another, a grinding wheel rotatably carried by one of the slides, means rotatably supporting a Work piece carried by the other slide, a trueing tool carried by the work supporting slide having a position adjacent the active face of the grinding \YllNl and a position remote therefrom, hydraulic means for effecting the translation of the grinding wheel slide and work supporting slide, a piston operatively connected with each slide and operated by the hydraulic means, a conduit for each piston, a valve in each conduit for controlling the flow of the hydraulic medium therethrough to control the movement of the slides and the position of the trueing tool, means for shifting the valves for stopping the movementof the grinding wheel slide, changing the rate of movement of the work supporting slide and for positioning the trueing tool adjacent the active face of the grinding Wheel and retracting same therefrom, a depressible plunger carried by the bed operable by theavork supporting slide for setting in motionthe last mentioned means, a second depressible plunger adjacent the work sup orting slide, and additional means carried b support-ing slide for depressing the said plunger to actuate the valves and establish a normal working cycle. ;;I 1

12. In a, grinding machine the-combinay the said work tion of a bed, a pair of slides carried thereby and translatable longitudinally thereof to ward and from one another, a grinding wheel rotatably carried by one of the slides, means rotatably supporting a work piece carried by the other slide, a trueing tool carried by the work supporting slide having a position adjacent the active face of the grinding-wheel and a position remote therefrom, hydraulic means for effecting the translation of the grinding wheel slide and work supporting slide, a piston operatively connected with each slide and operated by the hydraulic means, a conduit for each piston, a valve in each conduit for controlling the flow of the hydraulic medium therethrough to control the-movement of the slide and the position of the trueing tool,- means for shifting the valves for stopping the movement of the grinding wheel slide, changing the rate of movement of the work supporting slide and for positioning the trueing tool adjacent the active face of the grinding wheel and retracting same therefrom, means including a depressible plunger carried by the bed operable by the slide for setting in motion the last mentioned means and comprising a ratchet. mechanism operated by the said depressible plunger, a cam operativelyconn ectedwith the ratchet mechanism, a switch adapted to be closed by the cam, and an electrical circuit extending from the switch for throwing one tion of a bed, a pair of slides carried thereby means, a conduit for each piston, a valve in and translatable longitudinally thereof-to-.

ward and from one another,- a grinding wheel rotatably carried by one of the slides,

means rotatably supporting a work piece carried by the other slide,a trueing tool car ried by the work Supporting slide having a position adjacent the active face of the grinding wheel and a position remote therefrom, hydraulic means for effecting the translation of the grinding wheel slide and work supporting slide, a piston operatively connected with each slide and operated by the hydraulic each conduit for controlling the flow of the hydraulic medium therethrou h to control the movement of the slide and t e position of thetrueingtoo'honeofsaid valve'sefl'ecting'the starting and stopping of the grinding wheel slide and the other valve effecting a change in rate of movement of "the work supporting slide and for positioning the-trueing tool adjacent the active face of the'grinding wheel and retracting same therefrom, a depressible plunger carried by the bed adjacent the grind ing wheel slide, means carried by the said grinding wheel slide for depressing said plunger to effect a shifting of the valve to stop the movementof the said grinding wheel slide, said plunger being adapted to close a switch, and an electric circuit extending from the switch and completed by the closing thereof whereby the shifting of the stopping valve takes place. a

114. In a grinding machine the combination of a bed, a grinding wheel rotatably supported by the bed and shiftable longitudinally thereof, a truing tool carried by the bed and shiftable longitudinally thereof in a plane parallel with the plane of movement of the grinding wheel, means supporting the truing tool for movement toward and from the grinding wheel, means operableby the grinding wheel and truing tool during their translatory movements for stopping the movement of the grinding wheel and advancing the truing tool in the path of movement of the grinding wheel, and means for changing the rate of movement of the truing tool during the truing operation.

15. In a-grinding machine the combination of a bed, a grinding Wheel rotatably supported by the bed and shiftable longitudinally thereof, a truing tool carried by the bed and shiftable longitudinally thereof in a plane parallel with the plane of movement of the grinding wheel, means supporting the truing tool for movement toward and from the grinding Wheel, means operable by the grinding wheel and truing tool during their translatory movements for stopping the movement of the grinding wheel and advancing the truing tool in the path of movement of the grinding wheel, means for changingthe rate-of movement of the truing tool during the truing operation, and additional means for,retracting'thetruing. tool from the wheel at the conclusion of the truing operation and for re-initiating movement of the grinding wheel.

a grinding wheel on the bedand translatable longitudinally thereof, a work head rotatably supporting a work piece on the bed and trans, latable relative thereto toward and from the- 16. In a grinding machine the combination of a bed,'a wheel'head rotatably supporting remote therefrom, an hydraulic piston for actuating the wheel head, an hydraulic piston for actuating the work head, an hydraulic piston for shifting the truing tool, an hydraulic circuit commonto all the pistons for efl'ecting'their-movement, and a single valve actuable to various positions for effecting the normal translation of the wheel head and work head and retracting the truing tool to its inoperative osition and for modifying the.translation of the wheel head and work head and adjusting the truing tool toits operative position. v

17 In a grinding machinethe combination of a bed, a-wheel head rotatabl supporting a grinding wheel on the bed an translatable longitudinally thereof, a work head rotatably supporting a work piece on the bed and translatable relative thereto toward and from the rinding wheel, a truing tool on the work hea of movementof the grinding wheel for..efi'ect ing the truing operation, 'andat a point readapted to be positioned in the path mote therefrom, an hydraulic piston for'actuating the wheel head, an hydraulic piston for actuatin the work head, an hydraulic piston for shifting the truing tool, an hydraulic circuit common to all the pistons for effecting their movement a single valve actuable to various positions for eifecting the normal'translation of thewheel head and workhead and retracting the truing tool to its inoperative position and for modifying the translation of the wheel head'and work head and adjusting the truing tool. to its operative position, electromagnetic means for shifting the valve to" l itsseveral operative positions, and means operable by the wheel head and work head for energizing the electro-magnetic means.

18. In a truing device for truing the active face of an internal grinding wheel the combination of a bed, a slidesupporting the wheel for movementlongitudinally of the bed at a normal grinding stroke, a truing tool associated with the bed for truing the face-of the wheel and projectable from a point remote from the path of travel of the grinding wheel to a point in said path for intersecting said Wheel, and means for simultaneously stopping translatory movement of the grinding Wheel, shifting the truing tool from its inop- 5 erative position to a point in line with the active face of the grinding Wheel, and for shifting the truing tool longitudinally of the bed across the active face of the grinding wheel.

10 In testimony whereof we afiix our signatures.

CLEMENT BOOTH. FREDERICK S. HAAS. 

